As a conventional mixing reaction apparatus, the mixing reaction apparatus, and the chemical analyzer using the same, disclosed in Japanese Patent Laid-Open No. H6 (1994)-226071, are cited. The mixing reaction apparatus comprises a mixing chamber very low in profile, for executing mixing reaction, a multitude of minute nozzles provided at a high density on the bottom face of the mixing chamber, means connected to the minute nozzles, for feeding a liquid A (reagent), and a sample suction pump for sucking a liquid B (sample) into the mixing chamber, or feeding the mixing chamber with a cleaning liquid. Because reaction between the liquid B (the sample) as taken and the liquid A (the reagent) is instantaneously attained, a process of chemical reaction in which uniform mixing occurs and reaction takes place at a high-speed is measured on uniform concentration conditions.
Further, as another mixer, the liquid mixer, as disclosed in Japanese Patent Laid-Open No. 2001-120971, is cited. With the liquid mixer, respective liquid dividing narrow grooves for dividing a liquid A and a liquid B, as targets for mixing, introduced through a liquid inlet, and liquid mixing narrow grooves where branch flow paths of the respective liquid dividing narrow grooves are alternately linked with each other are formed in respective nesting faces of two plates, individually. In the liquid mixing narrow groove, the liquids A, B, in thin layers, respectively, are alternately stacked in the direction of the depth of the grooves, and are adjacent to each other, so that diffusion between the liquids A, B proceeds rapidly, and trace amounts of the respective liquids are mixed before flowing out of a liquid outlet.
Furthermore, as still another mixer, the micro-mixer, as disclosed in Japanese Patent Laid-Open No. 2002-346355, is cited. With the mixer, in a cell prepared by nesting and bonding a cell substrate and a cover together, an etching process is applied to the upper face of the cell substrate to thereby form respective inlet flow paths corresponding to liquids A, B, mixing flow paths, and an outlet flow path for a mixed liquid C.
[Patent Document 1]
Japanese Patent Laid-Open No. H6(1994)-226071
[Patent Document 2]
Japanese Patent Laid-Open No. 2001-120971
[Patent Document 3]
Japanese Patent Laid-Open No. 2002-346355
However, the inventors have found out that the embodiments disclosed in the above-described literature on the related art are not satisfactory for effectively mixing trace amounts of liquids. If the mixing reaction apparatus is applied to a gradient mixer (the gradient mixer is a mixer for mixing two kinds of solvent liquids while varying a mixing ratio thereof) installed mainly in a micro-LC (liquid chromatography), the following s are cited as problem points. When mixing two liquids at a minute flow rate, if a ratio of a flow rate of a liquid A to that of a liquid B is varied, for example, in case the flow rate of the liquid A is not less than 5 times the flow rate of the liquid B, there is a risk of occurrence of a problem in that the liquid B is not mixed with the liquid A, stagnation occurs, or so forth, in the mixing chamber of the mixing reaction apparatus described above, due to difference in flow velocity between the two liquids.
Further, a similar problem also occurs to the mixer described above if applied to the gradient mixer, and if a mixed solvent liquid from the mixer is injected into a column, which is a constituent component of a liquid chromatography, with two liquids in a state yet to be sufficiently mixed with each other, there has been encountered a problem that chemical components in liquid phase cannot be satisfactorily separated, resulting in failure to detect the chemical components with high precision in a subsequent process.